<p>
  <%= f.label :activity_id %><br />
  <%= f.text_field :activity_id %>
</p>
<p>
  <%= f.label :user_id %><br />
  <%= f.text_field :user_id %>
</p>
<p>
  <%= f.label :content %><br />
  <%= f.text_area :content %>
</p>